Eastern North Pacific Tropical Weather Discussion

000
AXPZ20 KNHC 192149
TWDEP
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2205 UTC Mon Mar 19 2018
Tropical Weather Discussion for the eastern Pacific Ocean from
the Equator to 32N, east of 140W. The following information is
based on satellite imagery, weather observations, radar, and
meteorological analysis.
Based on 1800 UTC surface analysis and satellite imagery through
2030 UTC.
...SPECIAL FEATURES...
Gale Warning: A cold front along a position from 30N131W to
21N140W is preceded by strong southerly flow north of 24N and
within 240 nm to its east, along with seas of 8 to 11 ft. A
deepening surface low pres system currently northwest of the
area will drop southeastward tonight behind this initial cold
front dragging a second cold front into the discussion area
accompanied by a strong to near gale southwest-west-northwest
wind shift. The pressure gradient will tighten around the
southwest semicircle of the low increasing the westerly winds to
minimal gale force winds in the range of 30 to 35 kt over the
discussion waters west of the front near 0900 UTC on Tue, with
associated seas of 15 to 16 ft. The low pres will lift north of
the area on Tue afternoon and winds will diminishing to 20 kt to
30 kt, and to 20 kt or less late Tue night. The associated NW
swell, in the form of 8 to 9 ft seas will propagate
southeastward through the waters covering the area west of a
line from the northern Baja peninsula to 07N129W early on Sat.
Please refer to the Pacific high seas forecast for more details
on this upcoming event under AWIPS/WMO headers MIAHSFEP2/FZPN03
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
A surface trough extends from 08N83W to 04N90W to 05N103W where
the ITCZ axis begins and continues along 05N103W to 06N120W to
06N140W. Scattered moderate isolated strong convection is noted
from 05N to 09N between 108W and 125W.
...DISCUSSION...
OFFSHORE WATERS WITHIN 250 NM OF MEXICO...
Surface high pressure of 1020 mb west of the northern Baja
Peninsula extends a ridge axis S to near 19N. This ridge will
shift slightly to the southeast through Tue, thus supporting
fresh to locally strong northerly winds on Jalisco, Mexico
offshore waters between 105W and 107W. Gentle to moderate
northerlies are over the Baja offshore waters diminishing to
light to gentle Tue night as the ridge weakens. These winds
along with 3 to 5 ft seas will continue through early Friday
morning when winds will increase to moderate again due to a
strong ridge building northwest of the area.
Gulf of California: Fresh to locally strong northwest flow is
forecast across the southern half of the gulf waters tonight
through Tuesday evening accompanied with seas to 7 ft.
Gulf of Tehuantepec: Strong to near-gale north flow will surge
through the gulf waters on early Wed morning, increasing to
minimal gale force Wed night. Gale conditions are then expected
to continue through Fri morning, with seas building to a maximum
of around 12 ft.
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND
WITHIN 750 NM OF ECUADOR...
Gulf of Papagayo: Fresh to locally strong NE nocturnal winds are
forecast starting Tue night and continuing through Wed evening
with seas building to 7 ft downstream. A stronger drainage event
is forecast to begin early Thu morning, and persist into the
upcoming weekend with seas building to 10 ft.
Gulf of Panama: Fresh to strong north nocturnal winds are
forecast starting early Thu morning through Sat night with seas
building to 8 ft.
Light to gentle offshore flow will prevail elsewhere.
REMAINDER OF THE AREA...
Please see see Special Features Section above for details on
upcoming gale force winds to impact the far NW portion of the
area in the short-term.
A very progressive pattern will continue to impact the the
northwest portion of the area well into this week. The deep
layer low pres system located to the northwest of the area and
its related trough is preceded by mid to upper level moisture in
the form of overcast cloudiness. Areas of rain along with
scattered showers and isolated thunderstorms under upper level
divergence that is present to the the east and southeast of this
low have moved over the area north of about 28N and west of 119W.
These clouds and precipitation will continue to advance eastward
towards southern California and the northern and central Baja
California through Wed per model moisture guidance fields.
$$
Ramos